Threaded fasteners frequently fail and become locked. The fasteners become locked by rust, corrosion, cross-threading, or through mis-use. Severely rusted fastener heads become smaller with less defined corners. Further, fastener heads are frequently damaged or rounded off. The end result is that the amount of torque which can be applied to the head of the fastener is minimized making removal very difficult.
Conventional tools such as wrenches and sockets cannot remove a failed fastener. Attempts at removal of a failed fastener usually exacerbates the problem by completely stripping the head of the fastener making it impossible to apply the necessary torque to the head. The user must resort to such drastic measures as cutting off the head of the fastener for removal. This usually damages the surface against which the head abuts.
Attempts have been made to provide a means of removing locked fasteners. U.S. Pat. Nos. 3,735,650; 4,366,733; 4,378,714; 4,757,729; 4,947,712; 4,970,917; 5,143,500; and 5,163,344; disclose examples of such devices. The adjustable sockets of the prior art are generally comprised of precision parts and intricate assembly. Accordingly, the devices of the prior are generally expensive limiting commercial success thereof.